A framework for modern communal-use shop management

Why care about about communal-use shop management?

Shops historically were not communal-use. There were essentially two categories: commercial/industrial shops and home shops. Commercial shops were part of a business, used by employees with low turnover, and typically focused on one or several manufacturing processes. Home shops had even lower turnover (on the order of one user per user lifetime), with more variety in projects but still limited because the number of users approximated one. Both were privately owned, used by a small set of users, and had low user turnover.

Communal-use shops typically have high user turnover, have user training as a top priority, and are used for a huge variety of projects and processes. They’re typically located within a makerspace or at an educational institution, though a few are within businesses.

There are a lot of these shops now. Popular Science says there were 483 in North America in February 2016. A 2015 survey by the Maker Education Initiative found that the 51 spaces surveyed served 1.8 million users annually.

Why communal-use shops are different and hard

As I’ve written elsewhere, the unique thing about a shop space is its versatility. Whereas a classroom is for teaching and a kitchen is for cooking, a shop can produce anything you can imagine. A shop could even be used to produce, in theory, another shop.

This near-limitless versatility is a double-edged sword. On the one hand, it’s what makes shops exciting, innovative, fun places. On the other hand, it’s what makes shops challenging to manage.

Versatility is a challenge for every shop, but especially so in communal-use shops. In traditional commercial shops, as management’s understanding of business conditions improves, they might choose to specialize in a particular process (say, centerless grinding) or industry segment (say, seat brackets for airliners). Over time, management gets better at knowing what tooling is needed most often, and how quickly it breaks or wears out, so tooling costs get more predictable. The same is true of other costs, like training and hiring employees.

But much of this is untrue in a communal-use shop space. Sure, some things get more predictable over time, like which tools tend to break most often, but:

  • The user base is by definition non-professional, with skill levels that are all over the place. Typically only a small proportion of users have much familiarity with the tools. This leads to more erratic maintenance and tooling costs.
  • The nature of the jobs/projects tends to be far more diverse. In most communal-use shops, the users (or perhaps their instructors) determine the projects. Shop management often has no control over what will be demanded in terms of processes, materials, and tools.

As a result, managing communal-use shop spaces is different from managing shops generally. The remainder of this post lays out a framework for communal-use shop management.

1. Understand stakeholders

Who are the stakeholders and what do they care about? What vision for the shop would satisfy them?

In an educational shop, for example, the list of stakeholders might include:

  • students
  • administration
  • faculty
  • parents

Ideally, you’d be able to rank these stakeholders by importance. Nobody loves ranking, say, students’ needs as subordinate to administrators’, but sometimes it’s necessary to do so, at least temporarily.

The better shop staff understand stakeholder wants and needs, the more successful the shop will be.

2. Define vision

Without a well-defined vision, the shop is doomed to failure.

At a high level, there’s a couple basic decisions that need to be made. For example, a shop generally either focuses on work orders (e.g. when a professor needs a widget for a research apparatus) or student projects and training.

Fortunately, it’s not that hard to start establishing a vision. A good way to start is to set some priorities. In an educational shop, for example, you might want student projects to be a higher priority than faculty work orders; work orders can be sent to outside shops, but student projects can’t.

Eventually, some lower-level decisions will need to be made, e.g.:

  • If the shop will be responsible for completing work orders:
    • If so, how will the priority of work orders be established?
    • Who will be responsible for completing work orders?
    • How, if at all, will work order costs be assigned to those submitting work orders?
  • What will be the access paradigm, i.e. who is allowed in the shop and when? Who will be responsible for setting the access paradigm?
    • How will access be controlled? Door key locks, machine key locks, RFID cards?
    • There may be some sets of tools with different access paradigms than others. How will this be controlled? Who will be responsible for setting these sub-paradigms?
  • What classes or training program(s) will exist?
    • Who will be responsible for designing and delivering them?
    • What users will be eligible for what trainings when?

3. Define role(s)

If and when staff like shop managers, machinists, student helpers, and volunteers, it’s folly to assume that these people will know what they’re supposed to do.

In contrast, when you hire, say, a mechanical engineer, the job description is more straightforward. Most MechE job descriptions are fairly similar both within a company, and between companies.

But shops are almost infinitely versatile, which means job descriptions within the shop can be almost infinitely diverse, both day-to-day and shop-to-shop. That is, the needs in a shop can change abruptly within a workday, and two shops that look similar from the outside might have vastly different needs (e.g. because they have different stakeholders and/or visions).

So it’s essential to set some boundaries. Will shop staff be responsible for setting policy, or merely for enforcing it? How will the staff’s performance be evaluated?

4. Culture first

Yea, I know, it’s supposed to be “safety first,” but give me a moment to show how focusing on culture can make a shop safer.

Let’s say you run a communal-use shop space and take the view that safety is what matters above all, and therefore any violation of the safety rules should be remedied with a stern and swift correction delivered by shop staff. What tends to happen as a result is that users respond to these incentives and always comply with the rules–but only when shop staff are present.

Instead, let’s say you frame safety as a cultural imperative. Rather than depending on you and other staff to deliver stern warnings, you encourage users to police other users in a collaborative, culture-building way, like maybe “Hey, I noticed you didn’t have safety glasses on, so here’s a pair for you.” Safety is framed as an ongoing responsibility of all users. Shop staff set the standards and the tone, but users help enforce cultural safety norms.

Which shop is safer?

Fortunately, most shop safety issues are long-term, not short-term. I’ve been working in shops for 10 years and I’ve seen an urgently unsafe condition on only a few occasions. Take safety glasses, for example. I am a proponent of all users wearing safety glasses at all times while in a shop environment. But this is not because there are acute eye injury hazards present in the shop. On the contrary, the hazard is a chronic one; hazard potential increases with time spent in the shop.

So although I’d prefer all users to always wear glasses in the shop at all times, when I see a user not wearing them, it’s more important to use this as an opportunity to build culture than to get safety glasses on the student as soon as possible.

Building healthy shop culture takes time. It’s the result of many tiny interactions, not a policy change. Humans build trust in tiny increments. Trust builds community; trust is community.

5. Balance safety and access

The safest shop is one that’s never open. Shops are full of hazards. The only way to guarantee safety is to prohibit access entirely.

That said, shops can be quite safe. I’ve been working in shops for 10 years now. The worst injury I’ve been around resulted in a part of a finger lost. The guy who sustained the injury still works in the shop. Unfortunate, and preventable, but not exactly deadly.

Taking a “safety first no matter what” approach likely promotes actions counter to the goals of the shop. Presumably you have a shop because you want things like faster prototyping. But if all you truly care about is safety, then having a shop isn’t a good idea.

I advocate seeing shop management as a balancing act between safety and access. With this approach, we can do things like identify which tools are most likely to cause problems, and then do things in response like prohibit user access to them, require special training before their use, or simply not buy them at all.

Shop management is NOT about reducing all safety risks to zero. That goal is incompatible with the existence of a shop. Rather, the goal is to find a spot on the safety-access continuum that works for all stakeholders, which inevitably means accepting some non-zero risks.

Why isn’t 3D metal printing more popular yet?

With the recent news that GE offered a total of $1.4 billion to buy two industrial 3D metal printing companies, 3D metal printing has been getting a lot of discussion. Spencer Wright has a great writeup.

Spencer’s analysis is that GE is making moves toward offering a complete array of industrial 3D metal printing solutions, including the various software packages that are part of an industrial 3D printing workflow.

GE is betting that metal printing will replace more traditional processes like machining, in which one starts with a block of material and removes the undesired stuff, or fabrication, in which one makes or buys, say, tubes, and welds them together. And, come to think of it, those traditional processes  sound so…inelegant compared to the efficiency of just printing whatever design one’s heart desires. So if metal printing is mature enough for GE (not known for high-risk maneuvers) to invest in it, why isn’t everything metal made by metal printing today?

1. Metal printing is different from plastic printing 
Unlike plastic printing, metal printing remains a largely industrial affair. The machines cost roughly $250,000 and up. There’s been no shortage of attempts to develop a consumer-grade, desktop metal printer, but none have had success even remotely approaching that of Formlabs and MakerBot. Meanwhile, plastic printers can now cost under $500.

The optimist in me says this is simply because the market is young and new. As one metal printing CEO put it,  “We’re in the early, early days of 3-D printing. If you think of aviation, we’re at the World War I stage, when planes were made of canvas and wood. This is an industry with a very long arc.” The pessimist wonders if the technical differences between metal printing and plastic printing will keep the price point too high for widespread consumer market penetration. As MakerBot co-founder Bre Pettis put it, There’s things that happen when metal melts. Aluminum you [melt] around 700 degrees. Does your oven go up to 700 degrees? You probably don’t want that in your house. (He must’ve meant Celsius; pure aluminum melts at 1,221° F, which is 660° C.)

Pouring the metal

2. Metal printing cost-benefits
Metal printing is neat, and will only become more commonplace and important with time. That said, it may be like autonomous vehicles in that it’s been a little overhyped; while the potential for disruption is huge, the “3D printed everything!!!1!!” future is a little further away than one might be led to believe based on the media coverage.

That’s because, for the moment, for most manufactured metal parts, 3D printing doesn’t offer enough benefit to justify rapidly displacing more traditional metal manufacturing methods. The chief benefits appear to be:
  • It’s possible to 3D print geometries that can’t be produced economically by other methods (machining, casting, forging, stamping, fabricating, etc.)
  • Material savings, because the printed part is closer to net shape and therefore uses only the minimum necessary material, where traditional methods produce more scrap (e.g. chips in machining and flash in forging).

(I’ve heard some chatter about an advantage in mechanical properties, i.e. that it’s possible to produce 3D printed metal parts with better hardness/strength/toughness/etc. than would be possible with other methods, which would be interesting for some specialized applications, but not for most mainstream applications that currently use cheap materials like mild steel or 6061 aluminum.)

At the moment, for most metal parts, material costs are insignificant. The cost of raw materials is such a small percentage of the cost of goods sold (COGS) that even relatively large changes in material costs have a relatively tiny impact on overall part COGS. There are a few reasons for this:

  • Metals are amazingly cheap. My own rule of thumb when buying steel is to budget $1/lb, and that’s for relatively tiny quantities; manufacturers buying thousands of pounds are probably paying far less. When you buy a block of, say, aluminum, you get that exact amount of usable aluminum, unlike, say, wood, where it’s not unusual to throw away 30% or 40% of a board. And metals are easy to store; they aren’t prone to distortion and they last forever (steel rusts eventually, but the oxidation rate is pretty slow, especially indoors).
  • Labor is so expensive that every other cost is small by comparison. In the welding industry, for example, labor generally makes up ~70% of costs. Welding filler metals typically represent only a small portion of overall welding costs, despite being relatively pricey as metals go.
  • Scrap metal isn’t necessarily waste. Industry magazines are full of ads for devices to convey, compress, and clean scrap chips, all to improve their sale price. I have a buddy who used to work for GE in supplier qualification. He qualified one supplier that did a lot of high-end machining of massive, intricate, expensive nickel castings used in GE jet engines. They told him they only broke even on the machining services; the profit came from selling their chips.

3. Beachead applications
Given the insignificance of material costs, the most important benefit of 3D printing in most applications is likely part geometry flexibility. The applications where this matters are being converted to printing.
Typically these beachead applications will be where:

  • costs to machine the part would be high, e.g. because
    • part geometry is complex or
    • the material is difficult/expensive to machine;
  • production quantities are low;
  • part volume is low (i.e. the part would fit in a relatively small box);
  • mix is high (i.e. there’s variation between similar parts, as in medical implants);
  • material costs are high (see above); and/or
  • weight is important (it can make more sense to print a part to be a lighter, rather than paying to machine away more material)

Aerospace is rife with these applications, and indeed SpaceX and Blue Origin reportedly use printed parts in their rocket engines. Another field that comes to mind is medical implants, especially those rendered in titanium, which can be a pain to machine..

I expect most of these low-hanging-fruit applications will be converting from machining, as it’s a process also generally well-suited to complex geometries, low production volumes, etc.

Automated turret punch press

4. Inertia
Even in applications where 3D printing demonstrably makes more sense than a traditional process, and especially outside specialized fields like aerospace and medicine, traditional processes will persist. Manufacturing is generally a change-averse, risk-averse industry. Traditional methods are traditional for reasons that matter, especially to the accountants:

  • Costs like maintenance and tooling are well understood.
  • Manufacturing machinery, like machining centers and turret punch presses, is expensive; it’s often either A. still being paid off, and therefore needs to be used frequently in order to justify its purchase, or B. been paid off already, in which case it generates (relatively) pure profit; either way, the accounts want the machinery used until it’s dead, which usually takes decades.

Perhaps more importantly, the large, well-resourced companies that make traditional machinery and tooling have long-established relationships with their customers, increasing the costs of entering these markets.

Why the Shop

An updated version of an essay I wrote back in 2009.

I’m a shop person who likes to read and write. My family and friends include plenty of liberal-arts types who wouldn’t know a Torx from a Phillips. This means a lot of questions like, “Why do you spend so much damn time in there?” “What’s so exciting about screw threads?”  “What’s the point of all this endless tinkering?”

It’s especially difficult to discuss because the shop isn’t necessarily a place I go to accomplish a specific thing. I might go there to work on one problem but end up working on the shop itself. Sometimes a tool is broken, so I spend an afternoon fixing it, or making a new one. That’s part of the fun.

Not many places are ambiguous in this way. A kitchen is for cooking; a classroom is for learning; a theater is for shows.  A shop is for working on things, but that includes the shop itself and everything in it.

Working in a shop can have a reflexive feeling, of constantly re-examining the tools, the process, the shop–even the people in the shop, including yourself.

A shop is a place where all variables are in flux. A mill, for example, could be used to produce a copy of itself. When you’re standing in front of a mill, the question is not “What is possible?” but now “What do I want to make?”.

In the shop, the only limitation is you. What projects deserve your time and effort?  It’s a nice metaphor for growing up.

Why machine tools and screw threads and such?  What cold, dispassionate things.

2015-07-30 09.59.48.jpg
The prettiest lathe: A Monarch 10EE I had the pleasure of using in 2014

It’s funny, because in my mind, these things carry warm emotional significance. There’s a feeling I get after I’ve been using a lathe for a while. I don’t mean any lathe, I mean one specific lathe, because each one has a personality. When I first start using it, I take my time carefully flipping every lever, making sure I don’t make a careless mistake. But over time the lathe and I come to an understanding. I learn its idiosyncrasies. After a few weeks of this, I’m flipping levers without looking. I know every control, every limitation of the machine. The words “sensual” and “intimate” come to mind.

It’s a little like raising a dog. I don’t view my relationship with dogs as one of dominance or obedience. The pinnacle of dog-human interaction is the feeling of partnership and collaboration that comes from working with a dog. Dogs excel at some things humans don’t (smelling things and body language), and we excel at some things they don’t (language and, maybe, reasoning). Similarly, the lathe isn’t entirely a servant but a partner, too.

These tools carry historical significance, too. It honors me to include myself in a tradition that bears includes great people doing great things.

It’s by learning to apply tools well that we have advanced past the stone age. Our survival depends on knowing how to manipulate our world with tools, and on continuing to pass on that knowledge.

By the way, besides being essential to everything we do, screw threads represent the culmination of all human experience. Their development is the result of many tiny decisions made by many people over many centuries. The most recent decisions were based on older decisions, which were based on yet older ones. That legacy goes back to the earliest humans. Without exaggerating, it can be said that screw threading standards have made fortunes and lost them.

In fact, every modern tool is a permutation of some simple, primitive tool. It was when we first started using these simple tools that we became technological–that we began a period of ever-increasing improvement upon what came before, of which we’re all beneficiaries.

Engineering is Marketing is Engineering

Why do we draw a line between engineering and marketing?

If the goal of marketing is to understand and develop solutions for that market, why stop short at the door to the engineering department?

If the goal of engineering is to develop solutions to real problems, why rely on the marketing department to determine what defines a real problem?

Especially in large companies that tend to have significant clout with educational institutions and accreditation agencies, the reasons for these division might include:

  1. There are inefficiencies in trying to teach one person to do two different jobs.The truth of this varies significantly by person, and by size of company (larger companies tend to favor compartmentalization more than small companies).
  2. Engineering is so technical that it requires years of specialized math and science to master, leaving little time for other topics.This is less true today than ever, not because the world is less complicated, but because computers can now do many of the analyses that used to be done by humans. In any case, there will always be science and math skills needed in engineering, but as individuals we have relatively little control over the degree to which computers can do this stuff for us. So other than staying on top of new developments, there’s not much we can do to change things here.
  3. Engineering is framed as a cost-minimizing, risk-mitigating activity, while marketing is seen as a driver of profits.This is the easiest to change, and thus has the biggest potential impact.

The lines between engineering and marketing are already blurry, and getting blurrier, but we would do well to better educate young engineers on the basics of marketing, and to foster close, trust-based working relationships between marketing and engineering.

Death to False Metal: Why Aluminum isn’t for Everything

It’s happened again: someone has asked me to weld something out of aluminum that would probably be better made out of something else. Probably stainless.

Aluminum is a great material. It machines well. Its corrosion resistance, even in not-terrifically-corrosion-resistant alloys like 6061, is plenty good enough for many applications. Did I mention it machines well? It’s really a machinist’s dream: soft but not gummy, brittle enough to form chips nicely, and with tons of thermal conductivity to draw heat away from the tool.

The problems usually arise when someone switches from designing aluminum machined parts to designing aluminum welded parts, which is a different animal entirely.

1. The welding itself.

First off, aluminum welding is more challenging than welding many materials, including stainless and mild steel, for a few reasons:

  • You need bigger, more pricey welding equipment. Although its melting temperature (~1100° F) is actually lower than that of steel (~2600° F), aluminum’s thermal conductivity is roughly double that of mild steel, so you really have to pour heat into it to get it to melt, which means bigger, more complicated welders.
    • Aluminum TIG requires AC, not the DC used for almost all other TIG applications. All TIG machines have DC, but not all have AC. In addition, many AC-capable TIG machines have AC-specific adjustments: AC balance, AC frequency, and/or AC waveshape. This adds complexity.
    • Sometimes this equipment is so big that it needs expensive electrical installations. A Miller Syncrowave 250, for example, is a common TIG machine that works well for aluminum. But it requires 93 amps of 230V single-phase power in order to run at its rated output. Have you priced that kind of electrical work lately?
    • If you don’t have a welder with enough juice, you can pre-heat the aluminum, e.g. with an oxy-fuel torch, but this complicates things further, including cleaning (see below).
    • MIG is of course faster than TIG, but aluminum MIG is especially pricey, as aluminum has low stiffness and therefore poor feedability. A spoolgun is the cheapest way to get started (~$800 and up) but they’re finicky little things. A push-pull setup is far better, but the gun alone can easily cost $2,000. In contrast, steel wire will feed well in a sub-$200 MIG gun.
  • The welding technique is harder. Aside from some expert aluminum welders, most folks find aluminum pretty challenging, especially at first. I’ve always taught it after teaching mild steel and stainless.
    • With TIG, the filler metal addition rate is significantly higher than with steels, so filler metal must be fed more quickly. 6061 is prone to cracking unless the foot pedal is tapered off to minimize crater size. Aluminum TIG requires far more pedal manipulation than is required for other metals.
    • With MIG, there are a variety of possible issues, including burnbacks, birdnesting, and porosity (which in my experience is more common with aluminum MIG than with aluminum TIG, and is overall vastly more common with aluminum than with steel or stainless).
  • Cleanliness is everything. Like stainless, aluminum is highly reactive, so much so that what we think of as aluminum is really a block of aluminum with a layer of aluminum oxide covering it. The oxide layer is usually thin, but aluminum oxide is a vastly different material: it’s roughly 3x harder (Source) and its melting point is 3.5x higher (Source and source). Its removal is critical to success in aluminum welding. This is generally best done with a hand-held stainless steel scratch brush. There’s a bit of technique to the brushing, which is best learned in person from someone who knows how, and the brushes used ought to be dedicated to this specific purpose to prevent cross-contamination.
  • Aluminum is its own universe. Many of the work practices, techniques, and consumables that work well for other metals don’t work for aluminum.
    • Aluminum behaves differently than steels as it heats up. There’s no orange or red glow to indicate temperature.
    • It can be terribly difficult to assess the alloy content (and therefore properties) of an unknown aluminum. With steels, the main alloying element is carbon. Carbon content is a huge factor affecting weldability of steels, and conveniently, carbon content can be assessed easily, e.g. by spark test or hardenability test. No such simple tests exist for aluminum alloys, and yet aluminum alloys vary more widely than steels in both alloying contents and properties than steels do, including huge variations in weldability.
    • Selecting filler metals for aluminum can be more complex than with steels. There are dozens of aluminum filler metals available. The two most common ones (ER4043 and ER5356) behave quite differently, so a well-equipped shop needs both, but users must be careful not to mix them up, as they’re essentially identical.
    • In contrast, switching from, say, mild steel to stainless steel, requires only a new filler metal and some small changes in machine settings and/or  torch technique. Someone with 20 hours of mild steel TIG experience can pick up stainless TIG in only a couple hours, but this hasn’t been true of people making a switch to aluminum in my experience.

2. Strength-weight ratio

At this point, you may be thinking, “Sure, it’s a bit of trouble to weld, but aluminum has such a fantastic strength-weight ratio that it MUST be worth all this trouble!” And you’re right…except you’re also wrong.

Let’s consider 6061-T6, as it’s by far the most common flavor of aluminum. Typically 6061 is supplied in the -T6 condition, as 6061-T6. The “6061” part just describes the alloying contents: 97% Al, 1% Mg, 0.6% Si, 0.3% Cu, etc. But 6061 is a heat-treatable alloy, so its properties vary dramatically depending on the heat treatment it’s had. That little “-T6” is a temper designation; it tells us what heat treatment has been done. In the case of -T6, it means the 6061 aluminum has been through a series of heat treatment operations, including heating to ~980° F  for an hour, rapidly cooling in water, then heating again, for anywhere from one hour at 400° F to eight hours at 325° F.

Why does this matter? Because it means that even though 6061-T6 is super strong stuff, as soon as you weld it, all that fancy heat treatment goes out the window, along with almost half the material’s tensile strength:

  • Typical 6061-T6 ultimate tensile strength (UTS): 45 ksi
  • Typical 6061 ultimate tensile strength as-welded: 27 ksi
  • Minimum expected 6061 ultimate tensile strength as-welded: 24 ksi (Source)

Oops, you know that super strong 6061-T6 you just welded on? It just got 40-47% weaker. To be fair, this weakening happens on a gradient, with the weakest part being nearest the weld (see Figure 2 here for more). In fairness, if we weld together two sheets of 6061-T6, there’s typically at least some part of each sheet still at the pre-welded strength of 45 ksi. But weakness near welds is really unfortunate, because welds and stress concentrations tend to be co-located.

If the goal was to have a material that’s strong and light (i.e. high strength-weight ratio), then this post-weld weakening business is bad news, because your aluminum weldment hasn’t gotten lighter, but it has gotten weaker:

  • UTS/density, 6061-T6: 462
  • UTS/density, 6061-T6, typical as-welded: 277
  • UTS/density, 6061-T6, minimum expected as-welded: 246
  • UTS/density, A36 mild steel: 204
  • UTS/density, 304 stainless: 253
  • UTS/density, 4130 “CrMo” steel: 342

(These are unitless ratios; higher numbers indicate a material that’s stronger per unit of density. Note that neither A36, 304, nor 4130 lose significant strength when welded properly.)

The main takeways:

  • 4130 has a strength-weight ratio 23% higher than as-welded 6061-T6 typically does. The major downside of 4130 is corrosion resistance, and while paint is a great solution to that problem, it adds weight and doesn’t stick around forever.
  • Even 304 stainless (not known for its super strength) may have a slightly higher strength-weight ratio than as-welded 6061-T6. And 304 is both easier to weld and more corrosion-resistant than 6061-T6. Its main downside is its relatively poor machinability.

3. Added uncertainty

Worse yet, the strength loss in as-welded 6061-T6 is variable depending upon a host of factors. As this aluminum welding guide puts it:

The as-welded mechanical properties of the 6xxx base metals are very sensitive to welding variables such as heat input and joint design

I’ll go a little further. As-welded, weldments rendered in 6061-T6 can vary in strength (and therefore strength-weight ratio) by up to 88%, depending on factors including:

  • location relative to the weld (farther from the weld being stronger)
  • heat input
  • joint design
  • filler metal selection
  • welding process

Welding 6061-T6 introduces undesirable uncertainty about the strength of the base material, which is stacked on top of other uncertainties, e.g. about weld quality.

4. Some caveats

A couple notes for my more technical readers (all both of you).

It’s possible, though typically not at a prototype scale, to post-weld heat treat (PWHT) a 6061-T6 weldment and thereby restore it to roughly the -T6 condition, i.e. with roughly 45 ksi UTS. I doubt this is within the realm of possibility for my readers. It requires an oven that goes up to about 1000 F, can maintain a consistent temperature for hours, and is large enough to fit your weldment inside it. Also, you’ll need to be able to move the nearly-1000-degree weldment out of this oven to dunk it in water. Also, your weldment will distort as a result of all this heating and cooling.

There are aluminum alloys besides 6061, and some of them lose significantly less strength after welding. The 5000 series in particular is attractive for welding applications, for a variety of reasons cogently elucidated in the Maxal aluminum welding guide I’ve referenced repeatedly. Sourcing 5000 series alloys can be a little tricky, but they are generally better for welding applications than 6061. Many of the 5000s bend nicely, too, whereas 6061-T6 often just cracks when bent (try it, it’s fun). Be sure to choose the right filler metal; many 5000-series alloys are best welded with ER5000-series filler metals, as opposed to the ER4043 (and, recently, ER4943) often used when welding 6061.

Similarly, there are aluminum alloys for which the PWHT process is vastly simpler. Alloy 7005, for example, can be post-weld aged at temperatures as low as 200° F, restoring much of its pre-weld strength. But you probably won’t find some kicking around the shop–outside of industries like bicycle frames, 7005 is rare bird.

5. Aluminum isn’t all bad

I’m not saying you shouldn’t use the stuff. Just don’t assume it’s the perfect material for all applications because you’ve used it for machined parts. Know that when you switch from machining it to welding it, you’re adding some significant risk and complexity.

And material selection is always a matter of compromise. 304 stainless, for example, welds easily, looks cool, and has great corrosion resistance…but it’s a pain to machine, it’s a little heavy for its strength, and it’s expensive. 4130 would be considered downright magical were it not for a couple limitations: it needs paint in most applications, and it’s not nearly as machinable as 6061-T6.

Until a perfect material is developed, we’ll have to settle with an assortment of less-then-perfect options…including aluminum.


Engineering Isn’t About Costs

Once upon a time, the job of the engineer was to minimize cost.

Engineers calculated things like

  • How thick does the concrete on this bridge deck need to be to ensure it won’t break?
  • What’s the maximum wind speed this house can endure?
  • What should the shape of this wind turbine blade be to maximize efficiency and minimize material?

Today, computers can answer questions like these. So why do we still have engineers? What do they do?

Engineers solve problems. That involves creativity, innovation, and passion. These have always been a part of engineering, but as computers take over more of the heavy mathematical lifting formerly done by humans, they’ll become even more important.

Of course, understanding costs is a crucial and often difficult part of engineering. But if we frame an engineers’ role as being all about reducing costs, we’re likely to get small, incremental changes. If we ask engineers to think bigger, like about what customers want, we’ll get bigger, better solutions.

Training ≠ Manufacturing

A factory in Faritabad, India, I visited in January 2014. This is not a training environment.

Recently I was at a customer site in the Midwest. These folks do…a lot of welding. They’re consistently one of the biggest 3 or 4 buyers of steel plate in the country. They buy so much plate that they don’t have to buy it in standard thicknesses like 1/2 inch or 3/8 inch; rather, they buy it in whatever size their engineers decide is best. One employee told me they can buy custom thicknesses like .433 inch cheaper than most companies can buy normal sizes like 1/2 inch. They buy a lot of plate, and then they do a lot of welding on it.

This site (one of dozens) is massive–easily the size of a couple of football fields. I was taken at one point to the “training area” at this plant. The training area felt like they had picked a random corner of the factory to stick it in.

It was loud. Not from the welding or the training that was happening, but from ambient noise.

It was poorly-lit. That is, there was more than enough light to see things happening around you, but nowhere near enough light for detail work, and welding training is most certainly detail work.

It was filthy. Not just in the sense that they needed to sweep up. More like there was just a lot of visual clutter around–old welding machines, spools of wire, work in progress, none of which were part of the welding training process.

Here’s the thing. Welding training is not welding. It’s not even manufacturing. It requires a different approach to do well.

The goal of a training center is to mold minds, not make widgets. The goal in a production environment is, primarily, efficiency; the main concerns are things like deposition rates and defect rates. The goal of a training center is to take untrained humans and turn them into (better-) trained humans. The goals are different, so the environments need to be different.

In a production environment, there shouldn’t be a lot going on besides production. As Peter Drucker put it, “A well-managed factory is boring. Nothing exciting happens in it because the crises have been anticipated and have been converted into routine.” The factory environment, then, doesn’t really need to foster communication beautifully. Communication isn’t the main priority; welding is. Yes, welders need to communicate, but not every second of the day, or even most seconds.

In a training environment, on the other hand, communication is everything. Training is communication. Communication moves the training process forward, and a lack of communication will hold it back.

So it’s imperative that a training area be quiet.

Similarly, it’s important for trainers and trainees to be able to see what they’re looking at. Details often matter in welding, so one might argue that good lighting is always necessary. But experienced welders can produce good work even under sub-optimal lighting conditions; this is in fact one way to define a welder as experienced. In my experience, inexperienced welders require good lighting to even do mediocre work.

There’s a school of thought that suggests that trainees should have to endure hardships identical to those they’ll experience on the job. I agree. In fact, the ideal training environment might expose trainees to hardships worse than those they’ll ultimately experience on the job. But, those hardships must be introduced gradually. Training is inherently stressful; adding hardships from the start only increases the dropout rate and makes the training take longer.

To sum up, let me contradict myself: in a sense, training actually is manufacturing, if we define “manufacturing” broadly. The goal is to produce something, even if that something is very different from a typical manufactured widget. As Peter Drucker said, we still need to anticipate crises and convert them to routine…it’s just that training involves a vastly different set of crises and routines. To be effective, training areas must reflect that.